The concept of electric current:

It is the flow of electrical charges through a conducting wire, as the electric charge may be ions or electrons or both, and we can control the flow of electrical charge through the components of the electrical circuit, so when lighting a light bulb, for example, this means that an electric current is caused by the transmission The free electrons and their dashing speed inside the wire atoms, which made the lamp light up.

Current unit:

According to the SI system, the electric current is measured in amperes, and the electric current is measured by an ammeter.

Types of electric current:

• Constant current: electrical energy moves within the electrical circuit in one direction, where electrons flow from the cathode to the anode, and the direction of current remains constant with the constant voltage and current regardless of time change, and this type is used in low-voltage applications, such as the currents used in solar cells Or batteries.
• Alternating current: the direction of electron flow in the electrical circuit changes several times per second, due to the alternation of the negative and positive poles, and this type is used when connecting large generators and motors.

Characteristics of electric current:

Electric current has several characteristics that distinguish it:

• Electric potential difference: There must be several conditions to enable the flow of current, and among them there must be an electrical voltage between two points, and the electric voltage refers to the force produced by a group of electrons in one place greater than the force of electrons in another place, and the greater force pushes the electrons from the place The first is towards the second place.
• Electrical resistance: The path in which electrons travel is also necessary for the flow of current, as some materials provide the possibility of this flow while it does not apply to some other materials, and electrical conductivity, which is one of the natural characteristics, depends on its resistance to the movement of electrons, as electrons in some materials are linked by chemical bonds They are not available to conduct an electric current, and in some other materials the numbers of electrons are free to move and flow easily.

Electricity risks:

One of the most obvious dangers of electricity is an electric shock caused by the flow of electric current through a part of the body. The effect of an electric shock is determined by the amount of electric current flowing through the body, which depends on the nature of the contact, the condition of this part of the body, the path of the current flowing through it, and the voltage value of the current source. While a very small amount of electrical current may cause a slight tingling sensation, too much of it may cause serious burns if passed through the skin or cardiac arrest if enough of it passes through the heart. The effect of electric shock varies significantly from person to person. Unintended electrical heating may also be dangerous. Overloading on power cables is a frequent cause of fires. Likewise, if a small battery is placed in a pocket with coins, this may lead to the formation of a miniature circuit that heats the battery and the coins, which may lead to burns.